MitoNEET-dependent formation of intermitochondrial junctions

Abstract

MitoNEET (mNEET) is a dimeric mitochondrial outer membrane protein implicated in many facets of human pathophysiology, notably diabetes and cancer, but its molecular function remains poorly characterized. In this study, we generated and analyzed mNEET KO cells and found that in these cells the mitochondrial network was disturbed. Analysis of 3D-EM reconstructions and of thin sections revealed that genetic inactivation of mNEET did not affect the size of mitochondria but that the frequency of intermitochondrial junctions was reduced. Loss of mNEET decreased cellular respiration, because of a reduction in the total cellular mitochondrial volume, suggesting that intermitochondrial contacts stabilize individual mitochondria. Reexpression of mNEET in mNEET KO cells restored the WT morphology of the mitochondrial network, and reexpression of a mutant mNEET resistant to oxidative stress increased in addition the resistance of the mitochondrial network to H 2 O 2 -induced fragmentation. Finally, overexpression of mNEET increased strongly intermitochondrial contacts and resulted in the clustering of mitochondria. Our results suggest that mNEET plays a specific role in the formation of intermitochondrial junctions and thus participates in the adaptation of cells to physiological changes and to the control of mitochondrial homeostasis.mitoNEET | CISD1 | mitochondria | intermitochondrial junctions | endoplasmic reticulum

Mitochondrial Morphofunction in Mammalian Cells

“…This study also provided evidence that MFNs are not required for IMJ formation and that IMJs are dynamic structures, the amount and function of which are dynamically regulated by the bioenergetic state of the mitochondrion. It was recently demonstrated that knockdown of MitoNEET (CDGSH iron-sulfur domain-containing protein 1 or CISD1), a dimeric outer membrane protein, reduced IMJ frequency (402). This suggests that MitoNEET plays a role in the regulation of IMJ formation.…”

GPER and ERα mediate estradiol enhancement of mitochondrial function in inflamed adipocytes through a PKA dependent mechanism

“…Lastly, antimycin A (15μM) and rotenone (15μM), inhibitors of complex III and I, were added to shut down ETC function, revealing the non-mitochondrial respiration. Mitochondrial reserve capacity (spare capacity) was calculated by subtracting basal respiration from maximal respiratory capacity[38].3.8. Analysis of cardiolipin content3T3-L1 cells were seeded in cover slips placed in the culture plate and differentiated to adipocytes.…”

Quantitative Proteomics of Presynaptic Mitochondria Reveal an Overexpression and Biological Relevance of Neuronal MitoNEET in Postnatal Brain Development

“…Cardiac mitochondria isolated from mitoNEET‐deficient mice demonstrate a reduced oxidative capacity (Wiley et al ., ). Loss of mitoNEET in mouse embryonic fibroblasts (MEFs) reduces mitochondrial respiration, although this bioenergetics change appeared to be due to lower numbers of mitochondria (Vernay et al , ). We found reduced mitochondrial membrane potential in NIH/3T3 fibroblast cells following mitoNEET overexpression, which correlated with lower ATP levels, consistent with previous findings in fibroblasts (Kusminski et al , ).…”